Hasil untuk "Electric apparatus and materials. Electric circuits. Electric networks"

Mahima Goel, Adrian Hochgesang, Animesh Bhui et al.

Abstract Mechanically stable and flexible composite TE thin films based on PEDOT:PSS and AgSb0.94Cd0.06Te2 blend by hot pressing on porous PVDF substrate are fabricated. A considerable enhancement of S and σ is observed in the regime of 60–97.5 wt.% of AgSb0.94Cd0.06Te2. High Seebeck coefficients of up to 204.9 µV K−1 and a high‐power factor of 53.45 µW m−1 K−2 are obtained for 97.5 wt.% of AgSb0.94Cd0.06Te2 content. However, there is a decrease in electrical conductivity on bending or storage under air. No loss of mechanical integrity can be detected in the SEM of bent films. Ultraviolet photoelectron spectroscopy reveals that overall energy levels of composite systems are either similar to PEDOT:PSS (φ = 5.00 ± 0.16 eV, IP = 5.12 ± 0.02 eV) or AgSb0.94Cd0.06Te2 (φ = 4.43 ± 0.11 eV, IP = 4.57 ± 0.01 eV), depending on the blend ratio. Transport mechanisms are studied using Mott–Schottky measurements, and by calculating the weighted charge carrier mobility, which increases continuously up to 5.5 cm2 V−1 s−1 for the highest inorganic content. It is demonstrated that a high inorganic content TE composite results in a flexible TE film achieving 80% of the Seebeck value of the pure inorganic component.

Ratiba FELLAG, Mahmoud BELHOCINE, Meziane HAMEL

This paper addresses the challenge of optimal Proportional-Integral-Derivative (PID) controller tuning for coupled Multi-Input Multi-Output (MIMO) mechatronic systems and validates the solution on a Quanser Aero 2 dual-rotor helicopter platform. The primary challenge in controlling such systems lies in satisfying conflicting performance objectives, namely, minimizing tracking error while simultaneously reducing control effort to ensure energy efficiency and respect physical actuator limitations. To address this, the controller tuning problem is formulated as a dual-objective optimization problem. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) is applied to obtain a diverse set of Pareto-optimal solutions that characterize the inherent compromise between tracking accuracy and control effort. The methodology is validated through simulation and experimental validation, demonstrating significant performance gains over a conventional PD controller. A rigorous comparative analysis using multiple performance indices (ISE, ITAE, RMSE) provides a quantitative assessment of the different solutions on the Pareto front. The results confirm that the NSGA-II approach provides a systematic and effective method for designing high-performance, robust, and practical controllers for complex MIMO systems. The compromise solution from the Pareto front offers an excellent balance of responsiveness, stability, and energy efficiency in both simulation and real-world experiments.

Ekasakti Karuniawan, Dinar Nugroho Pratomo

Kerumitan teknologi memengaruhi proses pengembangan dan pengujian aplikasi, yang bertujuan untuk memastikan aplikasi berfungsi sesuai dengan persyaratan dan bebas dari kesalahan. Dalam studi kasus aplikasi Propertio.id, dilakukan perbandingan antara metode pengujian manual dan otomatis menggunakan Selenium WebDriver serta Katalon Studio. Metrik yang dianalisis mencakup cakupan pengujian, waktu pelaksanaan, efektivitas pengujian, dan efisiensi perangkat lunak. Pengujian manual terbukti lebih unggul dalam hal cakupan pengujian (100%) dan efektivitas pengujian (11,5%), terutama dalam mendeteksi masalah UI/UX. Sebaliknya, pengujian otomatis lebih efisien dalam menangani operasi berulang, dengan waktu pelaksanaan yang 84,54% lebih cepat menggunakan Selenium. Selain itu, perbandingan alat pengujian otomatis menunjukkan bahwa Selenium lebih efisien dalam penggunaan RAM (21,8%) dan CPU (13,5%). Penelitian ini menyimpulkan bahwa pemilihan metode pengujian yang sesuai dengan kebutuhan kasus uji dapat meningkatkan efektivitas dan efisiensi dalam proses pengembangan aplikasi.

Bilel HERMOUCHE, Youcef ZENNIR

This paper produces a distributed control system to be used for collaborative UAV quadrotor simultaneous hovering and yawing missions in a leader-follower architecture, PID control is used in the altitude controller and the yaw controller for each single quadrotor with well-tuned parameters provided by two multi-objective optimization algorithms MOTEO and MOGOA, in the simulation and discussion section we show that due to the well system performances the produced parameters by MOTEO-PID combination are chosen to be the gains of the altitude and yaw controllers of the distributed control system for the hovering and yawing mission using a leader-follower architecture.

Bixin Yan, Valentine Gillioz, Ipek Efe et al.

Ferroelectric materials are established candidates for beyond complementary metal-oxide-semiconductor technology, owing to their non-volatile spontaneous electrical polarization. The recent boom in electric dipole texture engineering and manipulation in such materials has revealed exciting routes for controlling ferroelectric polarization, offering alternatives to the classical, sometimes challenging, application of electrical fields. In this short perspective, we shed light on electrode-free external stimuli enabling control over polar states in thin films. We bring awareness to the polarizing role of chemically-engineered surface contributions and provide insights into the combination of chemical substitution and mechanical pressure, complementing the polar state tuning capabilities readily enabled by flexoelectricity. Finally, we describe recent developments in the optical modulation of polarization. Thus, our perspective aims to stimulate the advancement of alternative means to act on polarization states and facilitate the development of ferroelectric-based applications.

Ralf Siemieniec, Martin Wattenberg, Ertugrul Kocaaga et al.

The introduction of 400 V SiC MOSFET technology bridges the voltage range gap between 200 V medium-voltage MOSFETs and 600 V super-junction MOSFETs. This technology is characterized by low switching losses and low on-state resistance, making it suitable for 2-level topologies in 120 VAC or 300 VDC systems or 3-level topologies with typical input voltages ranging from 180 VAC to 350 VAC or 400 VDC to 600 VDC.The technology concept is presented, and its efficiency and power density gains are demonstrated through measurements on test boards representing a 3-level ANPC general purpose inverter and a 3-level FC PFC for highly-efficient power supplies.

Yuki Usami, Tomoyo Fukumaru, Yuya Kawashima et al.

Abstract Neuromorphic computation has the potential to reduce the energy and resource costs associated with conventional digital computing. Nanomaterials are highly suited for use in neuromorphic computing devices. In this study, locally‐doped sulfonated polyaniline networks incorporating Au‐nanoparticle (SPAN–AuNP networks) are investigated using multiple microscale Au electrodes. Raman spectroscopy results of the SPAN–AuNP networks indicate that the SPAN molecules are partially dedoped in the regions surrounding the AuNPs. These dedoped regions act as bottlenecks for the hopping conduction path and lead to diverse nonlinear current–voltage characteristics that are dependent on the combination of the electrodes used, suggesting percolative conduction. The bottlenecks also act as charge‐trapping sites that impart long‐term hysteresis properties and enable the realization of a sum‐of‐products function. These results indicate that the design‐less SPAN–AuNP networks exhibit neuromorphic behavior similar to that of spiking neurons and thus have potential applications in in‐materia computing.

Shaofeng Wang, Qing Wang, Yuqiang Wu et al.

Abstract Twisted 2D bilayer transition metal dichalcogenides (TMDs) heterostructures exhibit rich physical properties due to the interaction of interlayer coupling and moiré superlattice effects. However, the influence of interlayer coupling changes induced by the twist angle on various TMDs properties still requires further exploration. To systematically investigate how the twist angle influences the structural, electronic and optical properties of TMDs, density functional theory (DFT) is used to examine 7 MoS2/WS2 superlattice heterostructures. Compared with that of the 2H stack, the interlayer coupling effect is weakened in the 21.79° and particularly 38.21° stacked heterostructures. A larger twist angle promotes an indirect‐to‐direct bandgap transition trend. Additionally, the twist angle can cause interlayer charge redistribution, which varies with the moiré pattern. Moreover, spin‒orbit coupling (SOC) causes a redshift by reducing the bandgap in the absorption spectra, and the twist angle suppresses interlayer direct transitions in the 𝜥 valley and alters the Raman and infrared spectra, with low‐frequency Raman modes providing a powerful tool for characterizing changes in interlayer coupling. These findings highlight the critical role of the twist angle in tuning the properties of TMDs heterostructures, with promising implications for optoelectronic and valleytronic applications.

Gajanan Pradhan, Federica Celegato, Alessandro Magni et al.

Abstract Magnetoelectric materials are one of the potential candidates that can counter the growing need of low‐power memory and spintronic devices due to their ability to electrically control magnetic states. Manipulation of a magnetic state with the sole use of an electric field has faced several challenges like volatility and non‐reproducibility. Here, we propose a magnetostrictive FeGa thin film interfaced with a relaxor ferroelectric substrate (PMN‐PT) having a [011] surface cut. The polarization rotation is controlled near the coercive electric fields and stabilized at remanence, which generates distinct strained states. This strain transfers to the FeGa layer mechanically, inducing a net rotation of magnetization without the need of any bias magnetic field applicators. Imaging of the magnetic domains reveals spatial and real‐time information about its variation and adds insight on the modification of magnetic anisotropy. The newly created magnetic information can be erased by reaching ferroelectric saturation and subsequently regenerated through specific electrical pulses. These results demonstrate the possibility of manipulating the magnetization via controlled polarization rotation, for use in strain‐driven magneto‐electronics.

Yunpeng Guo, Cheng Ma, Huanglong Li

Abstract Memristive physical unclonable function (PUF) is a recent entry to the list of security primitives, employing the intrinsic randomness of memristors. Although this represents a huge opportunity for memristors, all present memristive PUFs suffer from the problem of being device intensive because their entropies come exclusively from the spatial dimension. Here, a temporal PUF (TPUF) is reported, using the randomness of temporal dynamics of memristors as an entropy source. By exploiting temporal complexity, significant reduction of hardware overhead is achieved in the TPUF, from otherwise at least hundreds‐of‐memristors‐scale crossbar arrays to only a pair of memristors. This efficient and cheap TPUF can generate more than 1037 64‐bit challenge–response pairs (CRPs), whose number is infinitely up‐scalable (in principle) without hardware resource restrictions. Experiments have demonstrated that the TPUF has nearly ideal uniformity, diffuseness, uniqueness, low bit error rate, and NIST‐standard‐quality randomness. In addition, its hard‐to‐learn CRP relationship, forbiddingly large number of CRPs, and the potential slow‐down of the read‐out process make it highly resistant to machine learning attacks. This work represents a new opportunity for memristors for encryption.

Zhiyuan Duan, Peixin Qin, Chengyan Zhong et al.

Altermagnets represent a novel magnetic phase with transformative potential for ultrafast spintronics, yet efficient control of their magnetic states remains challenging. We demonstrate an ultra-low-power electric-field control of altermagnetism in MnTe through strain-mediated coupling in MnTe/PMN-PT heterostructures with negligible Joule heating. Application of +6 kV/cm electric fields induces piezoelectric strain in PMN-PT, modulating the Néel temperature from 310 to 328 K. As a result, around the magnetic phase transition, the altermagnetic spin splitting of MnTe is reversibly switched "on" and "off" by the electric fields. Meanwhile, the piezoelectric strain generates lattice distortions and magnetic structure changes in MnTe, enabling up to 9.7% resistance modulation around the magnetic phase transition temperature. Leveraging this effect, we implement programmable resistance states in a Hopfield neuromorphic network, achieving 100% pattern recognition accuracy at <=40% noise levels. This approach establishes the electric-field control as a low-power strategy for altermagnetic manipulation while demonstrating the viability of altermagnetic materials for energy-efficient neuromorphic computing beyond conventional charge-based architectures.

S. Sundara Pandiyan, Prabha Selvaraj, Vijay Kumar Burugari et al.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal).This article has been retracted at the request of the Editor-in-Chief.Similarities have been detected with a paper by different authors that had already appeared in the Journal of Cyber Security Technology, Volume 5, Issue 1, https://doi.org/10.1080/23742917.2020.1813396 (Lokesh and BoreGowda). One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. In the present case, a number of similarities were detected post-publication, in addition to concerns raised about the use of ‘tortured phrases' on PubPeer at https://pubpeer.com/publications/BC7201CFDDE1A8BF08C845A1BEF18E#1, and the authors' subsequent justification was not accepted. The scientific community takes a very strong view on such matters and apologies are offered to readers of the journal that this was not detected during the submission process.

Elliott Read, Simon Jones, James Marco

Six thermal runaway propagation tests were performed on small modules consisting of seven 21700 lithium-ion cells in a hexagonal configuration with 3 mm spacing between adjacent cells. One cell in the centre of the module was triggered into thermal runaway using an 8 mm diameter nail penetrated through the positive terminal of the cell. For half of the tests, sidewall rupture was initiated in the trigger cell using a 35 mm penetration depth. For the other half of the tests, sidewall rupture was not initiated in the trigger cell using a 10 mm penetration depth. In all tests where the trigger cell experienced sidewall rupture, there was thermal runaway propagation to the remaining six cells in the module; in all tests where the trigger cell did not experience sidewall rupture, there was no thermal runaway propagation to any other cells in the module. These results are explained by the directionality and magnitude of heat transfer for sidewall rupture failures relative to nominal failure. These results highlight the increased propensity for thermal runaway propagation when a sidewall rupture failure occurs in a battery module and emphasise the importance of methods to mitigate this failure in battery systems.

Joe W. Waters, Peter H. Siegel

Stratospheric ozone protects life on Earth from solar ultraviolet radiation, but the ozone layer is fragile. The Antarctic ozone hole has shown that humankind&#x0027;s release of certain chemicals into the atmosphere can deplete ozone essentially completely in a region where the destruction process is operative. Early detection of a future threat, especially one that might operate on a global scale as severely as that now operating in a layer over Antarctica each October, is crucial. Globally observing the stratosphere submillimeter-wavelength spectrum can give early (potentially earliest-possible) detection of threats to the ozone layer. Hundreds of chemical species &#x2013; including radicals that can reveal new destruction processes before they cause noticeable depletion of ozone &#x2013; have submillimeter spectral lines that are detectable and measurable at abundances that can threaten ozone. Spectral lines are resolved at all stratospheric heights, providing definitive identification. Chemical species in all global regions and at all stratospheric heights can be measured each 24-hour period, both day and night, including in the presence of dense volcanic aerosol and ice clouds. New solid-state technology is available for the stratosphere submillimeter spectrum to be observed from satellite at wavelengths down to 0.1 mm by both passive and active limb sounding. Using this technology, we present a Submillimeter Observatory for the Stratosphere (SOS) concept. SOS economically combines the most valuable features of passive and active measurements: vertical profile measurements of passive and ultra-high sensitivity of active. Active and passive measurements are time-shared, the passive system is the receiver for the active, eliminating the need for a separate receiver satellite. Active measurement vertical resolution is obtained from the measured spectral line shape, eliminating the need for a constellation of satellites. Instruments operate at ambient temperature, eliminating the need for detector cooling. Projected SOS detectability is given for 455 chemical species. Active measurement daily 10&#x00B0; latitude zonal mean precisions with 2 m antenna are projected capable of detecting 440 species down to &#x223C;10^&#x2212;12 relative abundances, and 220 species down to &#x223C;10^&#x2212;15. Passive individual vertical profile measurements, made every 1.5&#x00B0; along the suborbital path with &#x223C;2 km vertical resolution, have projected precision better than &#x223C;10^&#x2212;9 relative abundance for 390 species. Passive daily 10&#x00B0; latitude zonal means with 5 km vertical resolution have projected precision capable of detecting 200 species down to &#x223C;10^&#x2212;12. The fundamental limit on detectability is the stratosphere&#x0027;s spectral clutter floor. The practical limit is likely to be set by the ability to calibrate out instrumental spectral artifacts.

Oradee Srikimkaew, Saverio Ricci, Matteo Porzani et al.

Abstract This paper proposes a nanoparticle‐based atomic switch network memristive device, capable of both volatile and nonvolatile switching operations, which have not been previously reported for this material. The operational modes can be determined by altering the compliance current, demonstrating high stability over 100 cycles. Analysis of the conduction mechanism using I–V curves reveals switching characteristics consistent with space‐charge‐limited current conduction during the set process and ohmic behavior in the reset state. Furthermore, this study analyzes these dual‐operational modes in devices with varying electrode spacings. The results indicate that a wider spacing necessitated a higher compliance current for the volatile‐to‐nonvolatile transition, underscoring the significance of interconnection. These findings facilitate the integration of neuron and synapse functions within a single atomic switch network device, thereby advancing neuromorphic systems.

Kishore Anthuvan Sahayaraj K., Balamurugan G.

In this paper, proposed a novel method to improve the localization precision of identified objects. We present a framework for iteratively enhancing image region recommendations to meet ground truth values in this research. The Faster R–CNN (FR-CNN) seems to be an object recognition deep convolutional network. It gives the user the impression that the network is cohesive and single. The network can provide accurate and timely predictions about the whereabouts of a range of objects. We first build a unified model based on rapid predictions to relocate inaccurate area recommendations. Because the emphasis is on object detection, it may be utilised with a wide range of datasets and is compatible with various FR-CNN architectures. Second, we focus on the application of the joint score function to a variety of picture features. This joint score function depicts the location of the concealed object concerning other objects. The picture data and an updated structured production loss function are the only two inputs that influence the parameters of the joint scoring function. The join-score function and iterative context refinement (CIR) are used to generate our final unified model, which is then classified using Smooth Support Vector Machine (SSVM). We measured accuracy using the mean average precision after training FR-CNN + CIR and SSVM on a low-cost GPU using the PASCAL VOC 2012 dataset. Our results are 3.6 % more exact than rival deep learning algorithms on average.

Ameer Tamoor Khan, Shuai Li, Yinyan Zhang et al.

The paper proposes a novel nature-inspired optimization technique called Eagle Perching Optimizer (EPO). It is an addition to the family of swarm-based meta-heuristic algorithms. It mimics eagles’ perching nature to find prey (food). The EPO is based on the exploration and exploitation of an eagle when it descends from the height such that it formulates its trajectory in a way to get to the optimal solution (prey). The algorithm takes bigger chunks of search space and looks for the optimal solution. The optimal solution in that chunk becomes the search space for the next iteration, and this process is continuous until EPO converges to the optimal global solution. We performed the theoretical analysis of EPO, which shows that it converges to the optimal solution. The simulation includes three sets of problems, i.e., uni-model, multi-model, and constrained real-world problems. We employed EPO on the benchmark problems and compared the results with state-of-the-art meta-heuristic algorithms. For the real-world problems, we used a cantilever beam, three-bar truss, and gear train problems to test the robustness of EPO and later made the comparison. The comparison shows that EPO is comparable with other known meta-heuristic algorithms.

Tripura Pidikiti, Shreedevi, Gireesha B et al.

The addition of solar photovoltaic energy penetration to the electric grid is widely increasing across the world due to the many advantages such as clean energy source, easy to install and improved performance of power converters for the grid synchronization, and so on. Instead of many stages taking place for the grid-tied, a single stage is preferable to avoid the greater number of power electronic converters connected in the system which in turn reduce the cost of the overall system. In general, the DC-to-DC converters are used in the PV systems to track the maximum power point. However, an inverter circuit is needed to synchronize the source to grid and it can be utilized to extract maximum power from PV systems through proper controlling techniques. The proper control of inverter avoids the DC-to-DC power converter usage for the maximum power point tracking purpose. On the other hand, this technology can be used for small scale solar power plants. An irregular irradiance of solar is a bottleneck for the solar systems and to overcome it, a Takagi-Sugeno-Kang Fuzzy (TSKF) controller is designed for controlling the inverter operation in this paper. The TSKF controller responds very quickly to the input rapid changes of solar irradiance than the conventional proportional integral controllers. In this paper, a single stage 1 MW rating solar PV grid system is designed and verified the performance of the proposed controller under different loading conditions. Further, the proposed system is loaded with local loads and their reactive compensation is evaluated through hardware-in-loop on the platform of OPAL-RT software.

Teruo Matsushita

Kamal Saluja, Sunil Gupta, Amit Vajpayee et al.

End users are now encircled by an ever-increasing volume of information from edge devices relevant to a range of stakeholders, thanks to the introduction of edge computing in a variety of application domains. However, because of their distrust, these edge devices are unable to communicate significant amounts of data. The non-repudiation and non-tampering features of the block chain are used in this study to provide trust in collaborative edges. To address the limited processing capabilities of edge devices, create a block chain-based huge data sharing architecture in cooperative edges. Then, for high computational reduction, propose a Proof-of-Collaboration consensus technique, in which edge devices participate in block formation by giving their PoC credits. Furthermore, a useless transaction filter technique was proposed for transaction offloading, drastically decreasing the block chain's storage space in edges. Comprehensive tests are carried out to illustrate our proposal's better performance. Using this learning opportunity an environment friendly block chain sustainable infrastructure be created for developing countries.